Control for electric circuits



.Dec. 6, 1949 B. F. BRACY arm. I 2,490,251

CONTROL FOR ELECTRIC CIRCUITS Filed NOV. 1, 1945 amp/m 5: an/JnM/lv F. 524mg fan/Hen H. DALE),

Patented Dec. 6, 1949 UNITED STATES PATENT OFFICE 2,490,251 ooN'raoL FoI'tjELuc'T'RIo om'otir'rs Benjamin F. Bracy and Edward A. Daley, Belleville, 111.

Application November 1, 1945, Serial No. 626,142

6 Claims.

This invention relates to controls for electric circuits and has particular reference to a control Ior cutting off a liquid how in response to the volume of liquid delivered to a container.

The operation of filling tanks or 'cor'itai'ners; as now performed and as well known, must-be observed by the operator to prevent overflow. Particularly, in gas stations, when the attendant is filling the gasoline tank of a motor vehicle, it is required that the filling of the tank be observed and, thereby, time is lost which could be employed in other servicingwork during the filling period.

One applicationof the invention is to automatically stop the flow to such tank when a predetermined quantity of gasoline has been de--' livered to the tank. "Thls is only one example ofthe application invention as there are many commercial operations where it is advantageous to automatically cut ofithe flow to the container or vessel at a predetermined level.

An object of the invention, therefore, is to pro vide a device which is simple in arrangement and which will. effectively open an electric circuit when predetermined level of liquid has been delivered to a tank or container to stop the flow Another object is to provide a control which; after operation, is locked until operation is reestablished by manual control.

Specific further advantages of the invention will appear from theiollowing detailed descrip: tion taken in connection with the accompanying drawing, in which:

Fig. 1 illustrates diagrammatically the control system with the switch closed; and

Fig. 2 is a similar view illustrating the system with the circuit open.

In the embodiment of the invention selected for illustration, the control device is shown as in eluding three electrical circuits;

(a) To operate the device, which is part of. the

automatic controlrespons-ive to liquid level V in a tank orcontainer; I Y (b) To energize the operating unit, such. as a u p; and V (c) To control a circuit breaker lock forfth'e main control switch. through a shunt connection withthe main circuit.

The first circuit includes a main lead I, which is connected with one terminal of a motor 2, an element of the control system. A safety fuse 3 is preferably connected into the lead i. A lead 4 is connected to the other terminaI ofthe motor 2, and extendsto a circuit breaker point 5 carried (ma-pivot arm 6 of the circuit breaker. The

2 other lead I, of the control device circuit, extends to and is connected with a stationary contact point 8 of the circuit breaker.

The second circuit comprises leads 3 and I0 connected to put an operating device such as a motor M in parallel with the fan motor 2. This circuit is connected into such operating units as may be energized; for example, the device used as the means for causing the flow of liquid to a tank, such as the motor for the pump for the forced feed of liquid from a storage tank to a tank of a motor vehicle. It should be understood, however, that the control .may be employed in other embodiments for controlling power units, which it may be desirable to operate, responsive to changing conditions due to the accumulated volume of material advanced by the power unit to a tank or container.

The third circuit controls a circuit breaker lock and includes'a lead H which is electrically connected to a spring actuated solenoid armature lever Ila, the circuit being completed through a solenoid 12 by a shunt lead 13 from the line i, in which is interposed a resistance it.

The elements of the control device, which respond to liquid levels, include a conduit !5 having one branch 1'6 in communication with a suction fan unit ll, which is operated by the motor 2, and a second branch l8 connected into a diaphragm chamber.

It will be understood that the conduit i5 is designed to be adjustably supported in relation to liquid level of fluid delivered to a tank or container l9, through a filler opening 23, supplied from the power unit under the control of the electrical system.

It is contemplated that the conduit [5, which we have diagrammatically illustrated the drawings may be attached, for example, to th filler nozzle of a gasoline pump with its opening substantially aligned with the nozzle opening. By'this means, the positioning of the opening of the conduit 15 may be predetermined in respect of" the desired liquid level to be delivered to the tank. In other embodiments, the conduit i5 may be interposed into the tank or container at a predetermined height corresponding to the re quired predetermined volume of liquid to be delivered to the tank.

I The pressure-responsive device, under the infiuence of the suction in the conduit 13, includes a diaphragm chamber 2!, having a diaphragm 22. therein, the rear face of which carries a pull rod 23 which extends to and is connected with the circuit breaker. arm 6 by a pivot connection 24.

The fan device, when the opening to the conduit I5 is unobstructed, develops a partial vacuum pull in the conduit l5 substantially equivalent to the vacuum pull in the branch l8, thereby maintaining the diaphragm in the position shown in Fig. l, of the drawing. The surface pressure on the diaphragm being insuflicient to overcome the spring pressure of a spring 25, which forces the diaphragm outwardly, thereby maintains the circuit breaker arm in a vertical position, causing the points 5 and 8 to make contact.

When, for example, the level of the liquid delivered to the tank reaches a predetermined level and seals off the opening of the conduit [5, the fan, through the conduits I6 and I 8, increases the suction against the diaphragm 22 to such a degree as to flex the diaphragm inwardly, as illustrated in Fig. 2. This swings the arm 6 to the position shown in that view, opening the circuit between the points 5 and 8, thereby deenergizing the circuits. The fan I! is thereupon cut oif and the circuit, over the leads 9 and It to the operating unit or units, is deenergized.

The shunt circuit, through the solenoid i2, is

also deenergized as the switch 26 is normally open, causing the end of the spring actuated armature arm I la to move downwardly so that the extremity thereof seats behind the upper end 7 of the arm 6, as illustrated in Fig. 2. This circuit breaker lock will remain in locked position until the shunt circuit is energized and the operation is reestablished by closing a manual switch 26 interposed in the lead I 2. This raises the arm Ila and permits the main automatic switch to close. The operation is thereupon reestablished,

and will continue to operate while the opening of the conduit l5 remains open.

From the foregoing description, it will be understood that an efiicient, positively acting control has been provided, which fully accomplishes the purposes of the invention.

It is contemplated that changes in the form of the embodiment may be made that will be within the appended claims.

What we claim and desire to secure by Letters Patent is:

1. In a liquid level control responsive to liquid level in a container for operating an actuated means, a pressure chamber having a movable wall and actuated means operated by movements of the wall, a pneumatic connection into said chamber to produce a predetermined pneumatic pressure condition therein to move the wall, a relief connection to relieve the pressure condition in the chamber, said relief connection having an opening, means supporting the relief connection for disposition adjacent a varying liquid level, whereby the liquid may close the opening and cut off the relief connection, and the pressure condition may be developed in the chamber.

2. In a liquid level control responsive to liquid level in a container, a pressure chamber having a movable wall, a pneumatic connection into said chamber to produce a predetermined pneumatic pressure condition therein'to move the wall, a relief connection to relieve the pressure condition in the chamber, said relief connection having an opening, means supporting the relief connection for disposition adjacent a varying liquid level, whereby the liquid may close the opening and cut oil the relief connection, and the pressure condition may be developed in the chamber, and means actuated by the movement of the movable wall, said means comprising a cut-off mechanism, and a liquid pump motor for pumping liquid into the'container, operated by the cut-off mechanism and rendered inoperative by movement of the wall when the liquid closes the opening.

3. In a liquid level control responsive to liquid level in a vessel, a pressure chamber having a movable wall displaceable by changes in pneumatic pressure, pressure-producing means, a tube between the pressure-producing means and the chamber, a relief tube for relieving pressure in the chamber during operation'of the pressureproducing means, means supporting the relief tube above the liquid in the vessel for closure by the liquid when it reaches a predetermined elevation, whereby the pressure-producing means may produce pressure conditions in the chamber to move the movable wall, and actuated means connected for operation by the wall, said means including means to render the pressure-producing means inoperative.

4. In a liquid level control responsive to liquid level in a vessel, a pressure chamber having a movable wall displaceable by changes in pneumatic pressure, pressure-producing means, a tube between the pressure-producin means and the chamber, a relief tube for relieving pressure in the chamber during operation of the pressureproducing means, means supporting the relief tube above the liquid in the vessel for closure by the liquid when it reaches a predetermined elevation, whereby the pressure-producing means may produce pressure conditions in the chamber to move the movable wall, and actuated means connected for operation by the wall, said means including means to render the pressure-producing means inoperative, pumping means to deliver liquid to the vessel, and connections between said means and the actuated means for rendering the pumping means inoperative when the pressure-producing means is inoperative.

'5. In a liquid level control responsive to liquid level in a vessel, a pressure chamber having a movable wall displaceable by changes in pneumatic pressure, pressure-producing means, a tube between the pressure-producin means and the chamber, a relief tube for relieving pressure in the chamber during operation of the pressureproducing means, means supporting the relief tube above the liquid in the vessel for closure by the liquid when it reaches a predetermined elevation, whereby the pressure-producing means may produce pressure conditions in the chamber to move the movable wall, and actuated means connected for operation by the wall, said means including means to render the pressure-producing means inoperative, comprisin a switch, connections between the wall and the switch to move the switch between closed and open positions, the wall causing the switch to open when the liquid closes the relief tube, latch means to hold the switch open, and manually controllable means to withdraw the latch.

6. In a liquid level control responsive to liquid level in a vessel, a pressure chamber having a movable wall displaceable by changes in pneumatic pressure, pressure-producing means, a tube between the pressure-producing means and the chamber, a relief tube for relieving pressure in the chamber during operation of the pressureproducing means, means supportin the relief tube above the liquid in the vessel for closure by the liquid when it reaches a predetermined elevation, whereby the pressure-producing means may produce pressure conditions in the chamber to move the movable wall, actuated means connected for operation by the wall, said means 5 including means to render the pressure-producing i jneans inoperative, comprising a. switch, connections between the wall and the switch to move the switch between closed and open positions, the wall causing the switch to open when the liquid closes the relief tube, latch means to hold the switch open, and manugllg; controllable means to withdraw the latch, said' ni'enually controllable meanscomprising a solenoid end a switch in circuit therewith.

'7 v BENJAmN F.BRACY.

EDWARD A. DALEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,129,591 Schneider Sept. 6, 1938 2,318,355 Bailey May 4, 1943 

